Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: Chazashenefield on December 02, 2017,23:53:03
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Ok guys I'm new here and need some help. I acquired a Sharp LC-60E69U that had suddenly went black one day. There was still sound. The standby/power indicator light still works like normal. Because of these reasons I believed the main board was still good and the backlights inverters were bad. I tried the flashlight test a few different times with different people and no one could see anything on the screen. Though I can't be sure anything would be showing up even when hitting the menu button. I purchased replacement inverters and replaced them today. TV still does the same thing. My question is where do I go from here? I don't have much money to spend on this but would really like to fix the issue for obvious reasons. Any opinions or help is greatly appreciated. Thanks in advance.
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Some tellies can be pretty difficult to see with the torch trick the angle can be critical too.
If it was me I'd be concerned about getting the backlights working first, a no picture can be pretty much anything.
Seeing you have swapped the inverter the only thing then is to ask is the inverter being told to switch ON, there is usually a pin marked 'Bon' (backlight ON), I usually use a clapped out battery from a battery pack, about three volts is ample, providing the main voltage is up around 24V, the inverter should fire up with about +3V on the BLon pin and the negative lead on the metal work, that is how I test them sometimes, if you got doubts you can add a diode in series as a 'DC blocker'.
One thing you don't want overlook is sometimes the tubes are clipped in, I've seen them burn occasionally.... sometimes the tubes crack on the end, had one or two like that, I recently repaired a 23" Tesco Wonder Telly with cracked tubes... so I fitted a LED converter kit I got from Ebay far, far cheaper and reckon the picture is much more crisper.
Tesco Wonder Telly's are great...... nick the inverter and use it as a tube tester it'll fire up as soon as you apply 12V DC - Just an idea to throw some light.
I'd be tempted to try them tubes
Dave
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Given the history of display panel failures on these, another idea would be check for this. There are two wide flexi cables going from the T-Con to the panel. Disconnect one and check if a picture appears. Reconnect it and remove the other one. Check the picture again. If one situation results in a picture in half the panel, but not the other, then the panel itself is faulty. Bruce
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Thanks for the responses guys. I'll check the t conn connections and see if that does anything. I didn't really follow your explaination for the Bon and checking the voltage. If possible could you please break this down a little better for me? Sorry I'm pretty new at this.
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You have not specified if the TV's backlights are on or off. With the TV operating (such as it is), see if you can see light through any holes in the metal back lining of the display panel.
Re "Bon" mentioned by Davy, this is a voltage supplied by the main board to the power supply to activate the backlights. More commonly termed BL-ON
(backlight on) or INV-ON (inverter on). Bruce
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The backlights are not on at all and never flicker or anything. I'll have to get a multitester before I can check the voltage.